The name "Colombo", first introduced by the Portuguese in 1505, is believed to be derived from the classical Sinhalese name Kolon thota, meaning "port on the river Kelani". It has also been suggested that the name may be derived from the Sinhalese name Kola-amba-thota which means "Harbour with leafy mango trees". Due to its large harbour and its strategic position along the East-West sea trade routes, Colombo was known to ancient traders 2,000 years ago. However it was only made the capital of the island when Sri Lanka was ceded to the British Empire in 1815, and its status as capital was retained when the nation became independent in 1948. In 1978, when administrative functions were moved to Sri Jayawardenepura Kotte, Colombo was designated as the commercial capital of Sri Lanka.